Underreamer



' June 169 1931. E, F RAYMOND 1,810,030

UN DERREAMER Filed May 5, 1925 24 INVENTOR.

fdr/fard ffm/Umd By MMM/ 77M@e ATTORNEYS.

Patented June 1-6, 1931 UNITED STATES- iinwiinn IxnAYivIoND, orfsANfrAliin SPRINGS, CALIFORNIA, AssIeNon r.io JoiiN w.

PATENT oFFic A* MAccLATcIiIE', or coivIrfroN, CALIFORNIA UNDEILREAMER Application mea May y5,

. position.

, the latterV to be moved into 20 operative position.

The present invention has for an object the provision ofy a body having chambers, cutters mounted on axes longitudinally of ysaid body so as to be swung laterally, wherebyithe cutters will be housed. or sheltered within the body or extended beyond the body. Another object: of Athis invention is to provide anunderreamer ofthe character described which has cutters resiliently urged outwardly vinto projected, position and 4which Aby pressure upon the upper sides of the cutters will cause sheltered or in- Another object of y'the inventionis to provide the body for the expansible yand retractable cutters with a cooperating pilot end adapted to properly guide the tool as it is lowered through a well casing with the cutters retracted so that when the tool has been guided by the pilot end to position below. the y end of the'casing the cutters may automatically expand to operative position. l. Another object of the invention is to provide the pilot end which cooperates with the cutters, with suitable blades adapted to properly prepare the well bore for subsequent underreaming by the expanded cutters.

A still further object of so mount the cutters units which form the underreamer that they mayl swin' "and be held in expanded position simply y radial abutment against the body of thetooland Without the body circumerentially obstructing such swinging movement, and to'also provide for discharge of "a circulating fluid in back of the swinging cutter units when the latter are retracted, so that the fluid .discharge will cooperate with the described swinging mounting to expand thecutters and prevent any clogging action. l l

Another object of the invention is to pro-v vide for such discharge of a fluid circulating medium at spaced points along the length of the invention is toy 192e. seri-a1 No. 106,814.

the line 3 3 of Fig. l; Fig.' 4 is a vertical i section on an enlarged scale showing a fragment of the structure and particularly the mounting of the blades within the body; and

Fig. v5 is a section asseen yon the line 5-.5 of 1 Referring nmore particularly to the draw* ings, the invention is shown embodied in aV side tracking tool ofthe type shown in Patent 1,577,810, granted to me March Q3, 1926. It

comprisesva body A at the upper end of which Y is an annularY recess toreceive underreamer cutters .indicated generally by B. The lower 'end is provided with a tapered pilotend C.

-The vupper portion of tliefbody indicated. by 6 hasan overall cylindrical outer. wall.. At its 'uppermost end `it is Aprovided withy a taperedthreaded pin' 7 forfconnection to a string of'drillfpipe.v The intermediateportion `of the body isreduced in diameter 'to provide'a cylindrical mandrel 8. Extending longitudinally through theV body is a passage 9. for circulation'water from which extends courses 10 to theoutside above vthe annular chamber ll formed in the body. Passage 9 s reducedin diameter as indicated by l2 and watercourses 13 extending lthrough the mandrel communicate therewith. `A tapered internal threaded socket is formed at the lower end'of themandre'hand the pilot end() is connected thereto by' means cfa threaded pin. 'Extending longitudinally'through th portion of the vbodyb arek pivot pin bearing holes 14. There are four 'shownhereim there being four cutters for vthe v'underreamer The upper ends of the holes 14;V are internally fil lieve the pivotal mounting for the blades of the cutting stress and transmit it directly to the mandril; and the relative curvature of surfaces -25a of the bl ades and the cylindrical surface of mandril 8, whereby these surfaces are non-concentric with the pivot stems 26-27, fixes the cutters in operative position with suiiicient circumferential abutment between surfaces 25p-8 to aiord an adequate support but without extended frictional contact at these abutment surfaces, and particularly withoutextended frictional contact between surfaces 25 8 when the blades are swung to retracted position. Upon the tool being withdrawn into the casing, the bottom thereof or thefshoe engages the inclined portion or shoulder 31 of the bladeand due to the slightly non-radial position of the blade when in expanded position acts to swing the latter inwardly as the tool is with-` drawn into the casing,

What I claim is: 1. A tool of the character described comprising a body having an annular undercut external chamber and a downwardly extendf ing mandrel terminating in a pilot end having an upper wall forming a ledge outstanding from said mandrel, cutter bearing means supported by said ledge, cutters having trunnions at the ends for disposal in bearings in said body and said means, said cutters having heels movable into and out of engage-V ment with said mandrel, said cutters being so mountedl that when in expanded position cutting pressure exerted thereon will tend to swing them so that said heels will abut said mandrel thereby holding the cuttersrigidlyin outer position, and resilient means urging said kcutters into. expanded position.

2; A tool of the character described comprising a body having an annular undercut external chamber and a downwardly extending mandrel, a'pilot end 4depending from said mandrel and having an upper wall forming a ledge outstanding from said mandrel, a cutter bearing ring detachably mountreceiving trunnions at the lower ends of said' cutters, said cutters having heels movable 'into 1and outoicengagement withrsaid mandrel and being sol mountedA that when expanded cutting'pressure exerted thereon will tend l`to swing fthemso, that their heels will abutsaid m'andrels'thereby holding the? cuttersiigidly inouter position. f 3; A tool oftl'ie character described comprising a body having "anannular undercut external chamber and a downwardly extending mandrel, a pilot end detachably secured tosaid mandrel and having an upper wall forming a ledge outstanding from said mandrel, cutter bearing means vsupported by said ledge, `cutters having .trunnions at the ends for Adisposal inbe'arings in said body and said means, said vcuttershavingv heels movable int'o" and 'out of'engagement with said mandrel andbeing so mounted that when in expanded position ,Y cutting pressure exerted thereon will tend toswing them so that their heels will'abut said mandrel thereby. holdingthe cutters rigidly in outer position, resilient means urging said cuttersinto expanded position, said cuttershaving rearwardly bevelled outer edges inclined outwardly and downwardly for -engaging a casing at their upper'portion.

4. A tool otthe character described-com-y prisinga--body having an annular undercut external chamber and a downwardly extending mandrel, a pilot end detachably secured to said mandrel and having an upper wall forming a ledge outstanding from said mandrel, a cutter bearing ring detachably disposed-on said mandreland being secured thereto against rotation, said ring being sup'- ported by said ledge and having bearing' openings, cutters having trunnions at the ends for disposal in said bearing openings in said body and saidvring, said cutters having heels movable into and out ofengagement with said mandrel and being so mounted that when in expanded position cutting pressure exerted thereon will tend to swing them so that their heels will abut said mandrel thereby holding the cutters rigidly in outer position, resilient means urging said cutters into expanded position, saidv cutters having rearwardly bevelled edges inclined outwardly and downwardly for engaging a casing at their upper portion.

5. A tool of the character described comprising abody having an annular undercut external chamber and( a downwardly extending mandrel, there being bearing openings extending through said body at the overhanging portion, a pilot end detachably secured to said mandrel and vhaving an upper wall forming a ledge outstanding therefrom, a cutter bearing ring detachably mounted on said mandrel againstrotation and supported by said ledge, said ring having bearing openters having'heels movable into and out of engagement with said mandrel and being so mounted that-When in expanded position cutting pressure exerted thereon Will tend to swing them so thattheir heels Will abut said mandrel thereby holding the cutters rigidly in outer position', torsion springs mountedfin thze'bearing openings in said ibodyand `engaged with said-trunnions'urging said cutters into expanded'postion, said cutters having rearwardly bevelled edges inclined. out- Wardly and downwardly for engaging the lower end of a casing.

6. A tool of the character described comprising a body having an undercut shoulder and an axially projecting mandrel, anl outstanding bearing means axially spaced from the shoulder, a pilotend projecting axially beyond the bearingfmeans, a cutter having 2Q tru'nnions at its ends journalled respective- 1y in the shoulder and in the bearing means andadapting the cutter for swinging to expanded or contracted position, and a torsion spring on one of the journaled trunnions 2f tendingto swingthe cutter to expanded position.

In witness that Ivclaim the foregoing I have hereunto subscribedmyname this 27th dayof April, 1926.

EDWARD `ERAYMOND. 

